An important factor for managing the development and production of hydrocarbons from a reservoir is the reservoir pressure. The most common practice for determining reservoir pressure relies on pressure transient analysis (PTA) of the buildup or drawdown responses to a change in borehole conditions. However, when applied to tight gas formations. PTA methods can be inaccurate and unreliable. Fundamentally, such methods presume a measurable dynamic response, whereas the low permeability of a typical virgin tight gas formation yields insufficient gas flow for a meaningful dynamic measurement.
Another existing approach, known as rate transient analysis (RTA) or dynamic data analysis (DDA), attempts to address this issue by applying the fundamental flow-pressure relationships to a much larger data set, i.e., the production data. These methods match the production curves (including responses to changing borehole conditions) to type curves for pre-existing reservoir models. While these methods are more robust for tight gas formations than PTA, they unfortunately require a substantial amount of time to collect enough data points.
It should be understood, however, that the specific embodiments given in the drawings and detailed description do not limit the disclosure. On the contrary, they provide the foundation for one of ordinary skill to discern the alternative forms, equivalents, and modifications that are encompassed in the scope of the appended claims.